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#include <X11/extensions/Xrandr.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "config_ac.h"
#include "os_calls.h"
#include "string_calls.h"
#include "xwait.h" // For return status codes
#define ATTEMPTS 10
#define ALARM_WAIT 30
/*****************************************************************************/
static void
alarm_handler(int signal_num)
{
/* Avoid printf() in signal handler (see signal-safety(7))
*
* Prefix the message with a newline in case another message
* has been partly output */
const char msg[] = "\n<E>Timed out waiting for RandR outputs\n";
g_file_write(1, msg, g_strlen(msg));
exit(XW_STATUS_TIMED_OUT);
}
/*****************************************************************************/
static Display *
open_display(const char *display)
{
Display *dpy = NULL;
unsigned int wait = ATTEMPTS;
unsigned int n;
for (n = 1; n <= ATTEMPTS; ++n)
{
printf("<D>Opening display %s. Attempt %u of %u\n", display, n, wait);
dpy = XOpenDisplay(display);
if (dpy != NULL)
{
printf("<D>Opened display %s\n", display);
break;
}
g_sleep(1000);
}
return dpy;
}
/*****************************************************************************/
/**
* Wait for the RandR extension (if in use) to be available
*
* @param dpy Display
* @return 0 if/when outputs are available, 1 otherwise
*/
static int
wait_for_r_and_r(Display *dpy)
{
int error_base = 0;
int event_base = 0;
unsigned int outputs = 0;
unsigned int wait = ATTEMPTS;
unsigned int n;
XRRScreenResources *res = NULL;
if (!XRRQueryExtension(dpy, &event_base, &error_base))
{
printf("<I>RandR not supported on display %s\n",
DisplayString(dpy));
return 0;
}
for (n = 1; n <= wait; ++n)
{
printf("<D>Waiting for outputs. Attempt %u of %u\n", n, wait);
res = XRRGetScreenResources(dpy, DefaultRootWindow(dpy));
if (res != NULL)
{
if (res->noutput > 0)
{
outputs = res->noutput;
}
XRRFreeScreenResources(res);
}
if (outputs > 0)
{
printf("<D>Display %s ready with %u RandR outputs\n",
DisplayString(dpy), outputs);
return 0;
}
g_sleep(1000);
}
printf("<E>Unable to find any RandR outputs\n");
return 1;
}
/*****************************************************************************/
static void
usage(const char *argv0, int status)
{
printf("Usage: %s -d display\n", argv0);
exit(status);
}
/*****************************************************************************/
int
main(int argc, char **argv)
{
const char *display_name = NULL;
int opt;
int status = XW_STATUS_MISC_ERROR;
Display *dpy = NULL;
/* Disable stdout buffering so any messages are passed immediately
* to sesman */
setvbuf(stdout, NULL, _IONBF, 0);
while ((opt = getopt(argc, argv, "d:")) != -1)
{
switch (opt)
{
case 'd':
display_name = optarg;
break;
default: /* '?' */
usage(argv[0], status);
}
}
if (!display_name)
{
usage(argv[0], status);
}
g_set_alarm(alarm_handler, ALARM_WAIT);
dpy = open_display(display_name);
if (!dpy)
{
printf("<E>Unable to open display %s\n", display_name);
status = XW_STATUS_FAILED_TO_START;
}
else
{
if (wait_for_r_and_r(dpy) == 0)
{
status = XW_STATUS_OK;
}
XCloseDisplay(dpy);
}
return status;
}
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